Association between hospital mortality and inspiratory airway pressures in mechanically ventilated patients without acute respiratory distress syndrome: a prospective cohort study.

BACKGROUND

Higher inspiratory airway pressures are associated with worse outcomes in mechanically ventilated patients with the acute respiratory distress syndrome (ARDS). This relationship, however, has not been well investigated in patients without ARDS. We hypothesized that higher driving pressures (ΔP) and plateau pressures (Pplat) are associated with worse patient-centered outcomes in mechanically ventilated patients without ARDS as well as those with ARDS.

METHODS

Using data collected during a prospective, observational cohort study of 6179 critically ill participants enrolled in 59 ICUs across the USA, we used multivariable logistic regression to determine whether ΔP and Pplat at enrollment were associated with hospital mortality among 1132 mechanically ventilated participants. We stratified analyses by ARDS status.

RESULTS

Participants without ARDS (n = 822) had lower average severity of illness scores and lower hospital mortality (27.3% vs. 38.7%; p <  0.001) than those with ARDS (n = 310). Average Pplat (20.6 vs. 23.9 cm HO; p <  0.001), ΔP (14.3 vs. 16.0 cm HO; p <  0.001), and positive end-expiratory pressure (6.3 vs. 7.9 cm HO; p <  0.001) were lower in participants without ARDS, whereas average tidal volumes (7.2 vs. 6.8 mL/kg PBW; p <  0.001) were higher. Among those without ARDS, higher ΔP (adjusted OR = 1.36 per 7 cm HO, 95% CI 1.14-1.62) and Pplat (adjusted OR = 1.42 per 8 cm HO, 95% CI 1.17-1.73) were associated with higher mortality. We found similar relationships with mortality among those participants with ARDS.

CONCLUSIONS

Higher ΔP and Pplat are associated with increased mortality for participants without ARDS. ΔP may be a viable target for lung-protective ventilation in all mechanically ventilated patients.